Hyper-proliferative diseases like cancer and inflammation are attracting the scientific community to provide therapeutic benefits. In this regard efforts have been made to identify and target specific mechanisms which play a role in proliferating the diseases.
Tumor development is closely associated with genetic alteration and deregulation of cyclin-dependent kinases (CDKs) and their regulators, suggesting that inhibitors of CDKs may be useful anti-cancer therapeutics.
CDKs are serine/threonine protein kinases, which are the driving force behind the cell cycle and cell proliferation. CDKs regulate initiation, progression, and completion of mammalian cell cycle, and they are critical for cell growth. Most of the known CDK's, including CDK1 through CDK9, are involved either directly or indirectly in cell cycle progression. Those directly involved with cell cycle progression, such as CDK1-4 and 6, can be classified as G1, S, or G2M phase enzymes. Uncontrolled proliferation is a hallmark of cancer cells and the alteration of CDK function occurs with high frequency in many solid tumors.
The pivotal roles of CDKs, and their associated proteins, in coordinating and driving the cell cycle in proliferating cells have been outlined. The development of monotherapies for the treatment of proliferative disorders, such as cancers, using therapeutics targeted generically at CDKs, or at specific CDKs, is therefore potentially highly desirable. CDK inhibitors could conceivably also be used to treat other conditions such as viral infections, autoimmune diseases and neuro-degenerative diseases, amongst others. CDKs targeted therapeutics may also provide clinical benefits in the treatment of the previously described diseases when used in combination therapy with either existing, or new, therapeutic agents.
Therefore, a compound having an inhibitory activity on CDK will be useful for the prevention or treatment of cancer. Although CDK4/6 inhibitors were disclosed in the arts, e.g., WO2010020675 and WO2012064805, many suffer from having short half-life or toxicity. Therefore, there is a need for new CDK4/6 inhibitors that have at least one advantageous property selected from potency, stability, selectivity, toxicity and pharmacodynamics properties as an alternative for the treatment of hyper-proliferative diseases. In this regard, a novel class of CDK4/6 inhibitors is provided herein.